Get premium membership and access questions with answers, video lessons as well as revision papers.
- Use the diagram below to answer the questions that follow:(Solved)
Use the diagram below to answer the questions that follow:
a) Identify the radiations
A
C
b)The table below gives the rate of decay for a sample of radioactive element K. Study it and answer the question that follows:
Determine the half-life of element K.
Date posted: September 17, 2019. Answers (1)
- Other than cost and ability to conduct, give two other reasons why aluminum is used for making overhead electric cables while magnesium is not.(Solved)
Other than cost and ability to conduct, give two other reasons why aluminum is used for making overhead electric cables while magnesium is not.
Date posted: September 17, 2019. Answers (1)
- If 100cm3 of 0.05M hydrogen peroxide were used to produce gas M. calculate the volume of gas M produced if the hydrogen peroxide decomposed completely.(Solved)
If 100cm3 of 0.05M hydrogen peroxide were used to produce gas M. calculate the volume of gas M produced if the hydrogen peroxide decomposed completely.
Date posted: September 17, 2019. Answers (1)
- A student set up the apparatus as shown in the diagram below to prepare and collect dry ammonia gas.(Solved)
A student set up the apparatus as shown in the diagram below to prepare and collect dry ammonia gas.
(i) Identify one mistake in the set-up and give a reason.
(ii) Name a suitable drying agent for ammonia.
(iii) Write an operation for the reaction that occurred when a mixture of ammonium chloride and calcium hydroxide was heated.
(iv) Describe one chemical test for ammonia gas.
Date posted: September 17, 2019. Answers (1)
- Study the reaction scheme below and answer the questions that follow.(Solved)
Study the reaction scheme below and answer the questions that follow.
a) Name; Gas M
Precipitate w
b) Write an equation for the formation of ;
The white solid
Colorless solution X
c) What name is given to the process that produce precipitate W
d) State two commercial uses of gas M
Date posted: September 17, 2019. Answers (1)
- Below is a simplified diagram of the Downs cell in which sodium metal is manufactured.(Solved)
Below is a simplified diagram of the Downs cell in which sodium metal is manufactured.
(i) Identify electrolyte X and gas Y.
(ii)Give two properties of sodium that make it possible to collect as shown above.
(iii) Why is graphite preferred to steel as the anode?
(iv) Explain how sodium hydroxide pellets would be obtained from sodium amalgam?
Date posted: September 17, 2019. Answers (1)
- The grid below represents part of the periodic table. Study it and answer the questions that follow.
The letters do not represent the actual symbols of...(Solved)
The grid below represents part of the periodic table. Study it and answer the questions that follow.
The letters do not represent the actual symbols of the elements.
(i) Which element will require the least amount of energy to remove one of its outermost electrons, explain.
(ii) Select the most reactive non-metal
(iii) What name is given to the family of elements to which T belong?
(iv) Between S and R, which element has a smaller atomic radius, explain.
(v) Which of the elements have a tendency of forming covalent bonds? Explain.
(vi) Write the formula of the compound formed when U reacts with T, state the type of body formed.
Formula
Bond
Date posted: September 17, 2019. Answers (1)
- The scheme below shows various reactions and process for some organic compounds.
Study it and answer the questions that follow.(Solved)
The scheme below shows various reactions and process for some organic compounds.
Study it and answer the questions that follow.
i. Name process I and name any other product formed in the process.
Process
Product
ii) Name the reagent and condition required in process II.
Reagent
Condition
iii) Name the catalyst and reagent required in step IV.
Catalyst
Reagent
iv) Give any one use of the product formed in process (V)
v) Name process (VI)
Date posted: September 17, 2019. Answers (1)
- a)An organic compound G whose empirical formula is HCO2 has molar mass of 90. It reacts with ethanoic in the presence of a few drops...(Solved)
a)An organic compound G whose empirical formula is HCO2 has molar mass of 90. It reacts with ethanoic in the presence of a few drops of concentrated Sulphuric (VI) acid forming another compound J with a pleasant smell.
(i) Determine the molecular formula of compound G
ii)To which class of homologous series do compound G and J belong?
G
J
b)
i. What is vulcanization of rubber?
i). State two properties of vulcanized rubber
Date posted: September 17, 2019. Answers (1)
- Use the standard electrode potentials given below to answer the questions that follow.(Solved)
Use the standard electrode potentials given below to answer the questions that follow.
a) Select two half - cells which when combined will give the lowest e.m.f
b) Can a solution of silver nitrate be stored in a container of Zinc?
c) An iron jug was electroplated using Chromium. The chromium electrode and iron jug were thoroughly cleaned and weighed before being dipped into the electrolyte. Why was cleaning necessary?
d) A current of 0.75 Amperes was passed through the solution for one hour and four minutes. The mass of chromium deposited on the jug was 0.52g
(1Faraday = 96500C Cr = 52)
(i) Calculate the quantity of electricity passed.
(ii) How many moles in Chromium were deposited?
(iii) Calculate the quantity of electricity in coulombs required to deposit one mole of Chromium.
(iv) Deduce the charge of the Chromium ion.
Date posted: September 17, 2019. Answers (1)
- The electronic configuration of an ion P2- is 2.8.8..
Draw the structure of the atom just above element P in the periodic table.(Solved)
The electronic configuration of an ion P2- is 2.8.8..
Draw the structure of the atom just above element P in the periodic table.
Date posted: September 17, 2019. Answers (1)
- The atomic numbers of Li and K are 3 and 19 respectively.(Solved)
The atomic numbers of Li and K are 3 and 19 respectively.
Date posted: September 17, 2019. Answers (1)
- Study the following exothermic reactions involving enthalpy of neutralization.(Solved)
Study the following exothermic reactions involving enthalpy of neutralization.
Date posted: September 17, 2019. Answers (1)
- Urea (NH2)2CO is prepared by the reaction between ammonia and carbon (IV) oxide gas.
2NH3 (g) + CO2 (g)----->(NH2)2 CO (aq) + H2O (l)
In one process,...(Solved)
Urea (NH2)2CO is prepared by the reaction between ammonia and carbon (IV) oxide gas.
2NH3 (g) + CO2 (g)----->(NH2)2 CO (aq) + H2O (l)
In one process, 620kg of ammonia were reacted with excess carbon (IV) oxide gas.
Calculate the mass of the urea that was formed.
(H = 1.0, C =12.0, N = 14,O = 16 and RMM of ammonia is 17 )
Date posted: September 17, 2019. Answers (1)
- Compute the molar heat of combustion of butane, given that(Solved)
Given that
Date posted: September 17, 2019. Answers (1)
- The table below gives some bond energies of some bonds.(Solved)
The table below gives some bond energies of some bonds.
Calculate the enthalpy changes for the reaction.
Date posted: September 17, 2019. Answers (1)
- Study the information in the table below and answer the questions that follow.(Solved)
Study the information in the table below and answer the questions that follow.
Calculate the enthalpy change of the reaction:
Date posted: September 17, 2019. Answers (1)
- Study the diagram below and answer the questions that follow.(Solved)
Study the diagram below and answer the questions that follow.
i. State two observations made in the tube A
ii. Explain why the sand is heated first before heating the zinc metal
iii. Give the chemical test of gas X.
Date posted: September 17, 2019. Answers (1)
- The figure below represents a section of the periodic table. Study it and answer the questions that follow. The letters do not represent the actual...(Solved)
The figure below represents a section of the periodic table. Study it and answer the questions that follow. The letters do not represent the actual symbols of elements.
a) i).What chemical family does element J belong to?
ii. Compare the reactivity of element C and H. Explain.
b)
i) Write the chemical formula of the chloride of element D
ii) Name the type of structure of the chloride in b(i) above.
c). State and explain the difference in atomic radius and ionic radius of element F
d). Using dots (.) and crosses (x) show how bonding occurs when element E and F react.
Date posted: September 17, 2019. Answers (1)
- At 200C NO2 ; N2O4 gases exist in equilibrium as shown in the equation below.(Solved)
At 200C NO2 ; N2O4 gases exist in equilibrium as shown in the equation below.
(a) What is the significance of the negative sign as in the equation above.
(b) State and explain the observations that would be made when
(i) A syringe containing the mixture was immersed in warm water.
(ii) The volume of the gaseous mixture in the syringe was increased.
Date posted: September 17, 2019. Answers (1)